Zhao Yuewu, Wang Jine, Zhu Weipei, Liu Lifen, Pei Renjun
CAS Key Laboratory of Nano-Bio Interface, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China.
Nanoscale. 2021 Feb 28;13(8):4505-4511. doi: 10.1039/d0nr07834d. Epub 2021 Feb 18.
Metal-organic framework (MOF) nanomaterials with distinct matrix coordination-induced emission (MCIE) and quenching (MCIQ) effects were designed. The MOF structure can effectively restrict the intramolecular rotation of the organic linkers and enable the excited nanoparticles to exhibit the MCIE effect. However, if the ligand-to-metal charge transfer (LMCT) process occurs in the MOF structure, the fluorescence will be quenched and the excitation energy released in the form of non-radiative energy. When an electron donor is added to block the LMCT process, as expected, the fluorescence of the MOF nanomaterials is recovered. Therefore, the intramolecular LMCT process acts as a fluorescent switch in MOF nanomaterials that can effectively quench or enable their fluorescence. Additionally, the LMCT process is not affected by the morphology of the coordination compounds, even when the MOF nanomaterials are ground into amorphous structures. These results confirm that the fluorescence of MOF nanomaterials can be regulated by the LMCT process. This study has significance for guiding the design and synthesis of MOF nanomaterials with photoluminescence properties.
设计了具有独特的基质配位诱导发射（MCIE）和猝灭（MCIQ）效应的金属有机框架（MOF）纳米材料。MOF结构可以有效地限制有机连接体的分子内旋转，并使激发的纳米粒子表现出MCIE效应。然而，如果在MOF结构中发生配体到金属的电荷转移（LMCT）过程，荧光将被猝灭，激发能以非辐射能的形式释放。当加入电子供体来阻断LMCT过程时，正如预期的那样，MOF纳米材料的荧光得以恢复。因此，分子内LMCT过程在MOF纳米材料中充当荧光开关，可有效猝灭或激发其荧光。此外，即使将MOF纳米材料研磨成无定形结构，LMCT过程也不受配位化合物形态的影响。这些结果证实，MOF纳米材料的荧光可通过LMCT过程进行调控。该研究对于指导具有光致发光性质的MOF纳米材料的设计与合成具有重要意义。
